How to change the date format from mm-dd-yy to dd-mm-yy programatically

[pns.g...@gmail.com]

I want to know how the date format can be customized through dos.
Presently, i am using windows xp. In this the date format is mm-dd-yy.
But for me to run different applications or programs, i require the
date format to be dd-mm-yy. How can i change this programatically
without using control pannel's regional settings. Can you please
provide me a solution.

Thank u,
Ganesh